Soto‐Arenall, Matthew

Abstract Rationale Acute cellular rejection (ACR) within first-year post-lung transplantation has important implications for prognosis. Calcineurin inhibitors (CNI), including tacrolimus or cyclosporine, along with cell cycle inhibitors (CCI) and steroids, remain the standard immunosuppression regimen post-transplant. Although tacrolimus is used as the primary CNI, target therapeutic levels vary across recipients due to adverse effects and tolerability, sometimes requiring switching over to Cyclosporine. We hypothesized that ACR within the first year is associated with switching CNI from Tacrolimus to Cyclosporine. Methods We performed a cross-sectional study of 255 adult lung transplant recipients between June 2019 to November 2024 at Mayo Clinic, Florida. Demographics, induction regimens, CNI type and their levels (average low and high levels) were compared between the 2 groups. The institutional maintenance immunosuppression regimen is Tacrolimus, Mycophenolate Mofetil (MMF) and prednisone, but could be switched to Cyclosporine if the previous regimen is not tolerated. The primary outcome was ACR <1 year diagnosed based on biopsy and/or clinical criteria. Comparisons between groups were performed using Chi-Square test for categorical variables and t-test or Wilcoxon Rank sum test for continuous variables. Multivariable regression analysis was performed with ACR <1 year as the outcome to adjust for the confounders. Results Our cohort included 255 lung transplant recipients with median age of 63 years, 61% Male, 84% Caucasians, 88% bilateral lung transplant (Further details elucidated in Table 1). A total of 173 (67%) out of 255 patients had ACR <1 year. The group with ACR < 1 year had higher proportion of Interstitial Lung Disease (ILD) (81% vs 68%, p = 0.044), use of Basiliximab for induction (70% vs 55%, p = 0.018), and cyclosporine instead of tacrolimus (23% vs 11%, p = 0.027). Group with ACR <1 year also had higher Antibody Mediated Rejection (AMR) < 1year (15% vs 6.1%, p = 0.041) and higher CLAD (BOS 0p-3: 43% vs 25.6%, p = 0.033) compared to the group without ACR < 1 year (Table 1.1). Multivariate regression analysis showed ILD (adjusted odds ratio, aOR 2.84, 95% CI 1.31 - 6.27, p = 0.008) and use of cyclosporine (aOR 2.55, 95% CI 1.07 - 6.78, p = 0.034) as independent predictors of ACR < 1 year (Table 2). Conclusions The presence of ACR < 1 year was associated with the use of Cyclosporine over Tacrolimus as a maintenance regimen. Also, ACR < 1year was associated with higher AMR and CLAD. Further prospective studies are needed to study this long-term given its significant prognostic implications. This abstract is funded by: Not Applicable

Abstract Background Treating COVID-19 infection in SOT is challenging due to long-term use of immunosuppressive agents. REM is the only FDA-approved anti-viral for SARS-COV-2 infection. DEX showed decrease in mortality in the Recovery Trial. COVID-19 treatment guidelines for SOT patients are the same as NTP despite limited literature on those outcomes. Our primary objective was to determine if 30-day mortality was different between SOT and NTP matched cohorts using these 2 drugs. The secondary objectives included comparisons of length of stay (LOS), days on mechanical ventilation (DMV), and the use of other treatment modalities. Methods We retrospectively collected data for hospitalized SOT and NTP, 18 years and older, with pcr-confirmed SARS-CoV-2 infection receiving REM and DEX from May 1, 2020, to October 10, 2020, at Mayo Clinic Florida. IRB approval was obtained. Descriptive statistics were used to analyze the data. Continuous variables were summarized as mean (standard deviation) or median (range) where appropriate, while categorical variables were reported as frequency (percentage). Results Of 80 patients who met the inclusion criteria, 28 were SOT, and 52 were NTP. The SOT cohort was subcategorized below: SOT patients were significantly younger than NTP (p < .001). Further, SOT patients had significantly longer LOS (p = 0.043) and more COVID-19 modalities (75% vs. 36.5%, p = 0.002) compared to NTP. Among the 28 SOT patients, 2 of them died within 30 days of admission, and among the 52 NTP patients, 7 of them died within 30 days. The 30-d survival estimate for SOT group is 92.9% (95% CI: 83.8% - 100.0%) and for NTP group is 86.5% (95% CI: 77.7% - 96.3%). The log-rank test was not significant between the groups (p=0.37), but the NTP has a worse survival curve from the figure below. SOT-NTP Survival Curve Conclusion SOT group was younger, had longer LOS, and more COVID-related modalities. The 30-d survival estimate for SOT group is 92.9% and for NTP group is 86.5%, but the survival curve for NTP was worse likely secondary to age. Use of REM & DEX in SOT recipients is a valid recommendation. Disclosures Claudia R. Libertin, MD, Gilead (Grant/Research Support)